The present invention relates to certain N-phenyl-N'-benzoylureas, to a process for their preparation and to their use as arthropodicides, especially as insecticides and acaricides.
The invention provides, as new compounds, the N-phenyl-N'benzoylureas of the general formula ##STR1## wherein R and R.sup.1 are each independently a hydrogen or halogen atom, a C.sub.1 -C.sub.4 alkyl or a C.sub.1 -C.sub.4 haloalkyl group; R.sup.2 and R.sup.3 are each independently a hydrogen or halogen atom or a C.sub.1 -C.sub.4 alkyl group; R.sup.4 and R.sup.5 are each independently a hydrogen or halogen atom, or a C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 haloalkoxy, C.sub.2 -C.sub.4 alkenyl, C.sub.2 -C.sub.4 haloalkenyl, C.sub.2 -C.sub.4 alkenyloxy, C.sub.2 -C.sub.4 haloalkenyloxy or a C.sub.2 -C.sub.4 alkynyl group; R.sup.6 is ##STR2## wherein R.sup.7 and R.sup.8 are each independently a hydrogen or halogen atom, or a nitro, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl or cyano group and R.sup.9 is a halogen atom or a C.sub.1 -C.sub.4 alkyl or a C.sub.1 -C.sub.4 haloalkyl group.
The present invention also provides processes for the preparation of the benzoylureas of formula I.
In the present specification and claims, the terms halo, halogen, or the term halo as it is employed in haloalkyl, haloalkoxy, haloalkenyl or haloalkenyloxy designates bromo, chloro or fluoro.
In the present specification and claims the terms alkyl, haloalkyl, alkoxy, haloalkoxy designate straight-chained radicals of 1 to 4 carbon atoms or branched-chained or cyclic radicals of 3 or 4 carbon atoms; the terms alkenyl, haloalkenyl, alkenyloxy or haloalkenyloxy designates straight-chained radicals of 2 to 4 carbon atoms or branched-chained radicals of 3 or 4 carbon atoms; the term alkyl designates straight-chain radicals of 2 to 4 carbon atoms or a branched-chained radical of 4 carbon atoms.
In the first of these processes, process (a), a phenylazoaniline of the general formula: ##STR3## wherein R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are as defined above is reacted with a benzoylisocyanate of the general formula ##STR4## wherein R and R.sup.1 are as above defined in the presence of an appropriate solvent.
In the second of these processes, process (b) a 4-arylazophenylisocyanate of the general formula ##STR5## wherein R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are as above defined is reacted with a benzamide of the formula ##STR6## wherein R and R.sup.1 are as above defined in the presence of an appropriate solvent.
Employing 4-phenylazoaniline and 2,6-difluorobenzoylisocyanate as the starting materials, the reaction scheme of process (a) is set forth below along with the reaction scheme for process variant (b) wherein 4-phenylazophenylisocyanate and 2,6-difluorobenzamide are employed as the starting materials. ##STR7##
As indicated above, the processes for the preparation of the compounds of the invention are preferably carried out in the presence of suitable solvents and diluents. The particular solvent employed is not critical as practically all inert organic solvents can be used for this purpose, especially aliphatic and aromatic hydrocarbons and chlorinated hydrocarbons; additionally, ethers, ketones and nitriles can be employed.
The reaction temperature may be varied within a fairly wide range and can include reflux conditions. In general the reaction is carried out at a temperature in the range of from 0.degree. to 130.degree. C., preferably at room temperature. The reaction preferably takes place at atmospheric pressure.
In carrying out these above processes, the reactants are preferably employed in equimolar amounts.
The compounds of the present invention are normally crystalline solids having a low solubility in water and having a moderate solubility in many organic solvents. The componds have low phytotoxicity and have exceptional activity in the control of various undesirable agricultural, household and veterinary insect pests.
Examples of the various insects which can be controlled by the active compounds of the present invention are members of the orders Lepidoptera, Coleoprtera, Diptera, Orthoptera, Homoptera, Thysanoptera and Acarina. They are active against normally sensitive and resistant species at some stages of development. Examples of insect pests comprising the above include the tobacco budworm (Heliothis virescens), the beet armyworm (Spodoptera exigua), the Egyptian cotton leafworm (Spodoptera littoralis), the American bollworm (Heliothis armigera), the diamond-back moth (Plutella maculipennis), the gypsy moth (Lymantria dispar), the cutworm (Agrotis segetum), the Mediterranean flour moth (Ephestia keuhniella), the Colorado potato beetle (Leptinotarsa decimlineata), the mustard beetle (Phaedon cocheariae), the cotton boll weevil (Anthomomus grandis, the Mexican bean beetle (Epilachna varivestis), the khapra beetle (Trogoderma granarium), the housefly (Musca domestica), the lesser housefly (Fannia canicularis), the Mediterranean fruit fly (Ceratitis capitata), the black blow fly (Phormia regina), the cabbage rootfly (Hylemya brassicae), the yellow fever mosquito (Aedes aegypti), the malaria mosquito (Anopheles stephensi), the desert locust (Schistocerca gregaria), the migratory locust (Locusta migratoria), the German cockroach (Blattella germanica), the American cockroach (Periplaneta americana), the pear psylla (Psylla pyricola), the onion thrips (Thrips tabaci), and the citrus rust mite (Phyllocoptruta oleivora).
The compounds of the present invention are highly active and can be employed to kill insects outright and/or to prevent adult emergence from the juvenile forms of the insect. In such applications, the insect to be controlled and/or its habitat is contacted or treated with an insecticidal amount of one or more of the compounds of the present invention. The compounds may be administered orally to warm blooded animals from which they are excreted unchanged and they effectively combat the larvae of certain insects which inhabit faeces, e.g., the face fly, horn fly and buffalo fly.
For all such uses, the compounds of the present invention can be employed in unmodified form. However, the present invention also includes within its scope the use of an insecticidally-effective amount of the active ingredient in composition form with a material known in the art as a diluent or carrier.
Thus, for example, compositions employing one or a combination of these active ingredients can be in the form of a liquid or a dust, and the adjuvant employed can be any one of a plurality of materials including aromatic solvents, petroleum distillates, water or other liquid carriers, propellant substances, surface-active dispersing agents, light absorbers and finely-divided carrier solids.
The exact concentration of one or a combination of the compounds of the present invention in a composition thereof with an adjuvant therefore can vary; it is only necessary that one or a combination of the compounds be present in a sufficient amount so as to make possible the application of an insecticidally-effective or inactivating dosage.
Generally, for practical applications, one or a combination of these active ingredients can be broadly applied to the insect larvae or their habitat in compositions containing from 0.0001 to 98 percent by weight, preferably 5 to 50 percent by weight, of the compounds.
The compounds of the present invention or compositions containing them can advantageously be employed in combination with one or more additional pesticidal compounds. Such additional pesticidal compounds may be insecticides, nematocides, acaricides, herbicides, fungicides or bactericides which are compatible with the compounds of the present invention in the medium selected for application and not antagonistic to the activity of compounds. Accordingly, in such embodiments, the pesticidal compound is employed as a supplemental toxicant for the same or for a different pesticidal use, or as an additive. The compounds used in combination which the compounds of the invention are generally present in a ratio from 1 to 100 parts of the compound of the present invention to form 100 to 1 parts of the additional compound(s).
The compounds of this invention are, or tend to be, slow acting, i.e., they disrupt the molting of the insect, thereby killing it. As a result, some time can pass before the insects are killed. Accordingly, an increased benefit can be obtained by combining the compounds of this invention with quicker acting insecticides such as, for example, organophosphorus compounds, carbamates and pyrethroids. Because of this different mode of action, the compounds of this invention kill or control the more common insecticides and thus they inhibit or delay the development of resistance to such insecticides.